Diesel engine fuels



. Patented Mar. 2 3,

UNITED: STATES PATENT OFFICE DIESEL ENGINE FUELS Robert T. Pollock, NewYork, N. Y.

No Drawing.

2 Claims.

'l'hisi-invention relates to internal combustion engine fuels andrelates more particularly to fuels for compression ignition engines andto methods and means for improving their ignition qualities.

Objects and advantages of the invention will.

be set forth in part hereinafter and in part will be obvious herefrom,or may be learned by practice with the invention, the same beingrealized and attained by means of the steps, compositions, combinationsand improvements pointed out in the appended claims.

The invention consists in the novel steps, compositions, combinationsand improvements herein described.

Objects of this invention are to make possible the raising of the'cetanenumber of fuels for compression ignition engines without lowering, orwithout substantial lowering of the flash point of the fuel and withsome lowering of the pour point of the fuel; and, to accomplish theforegoing through the use of an addition agent or additive materialwhich is stable and will not decompose under normal storage conditions,which is non-toxic and non-explosive and is non-inflammable at roomtemperature and which is liquid even at very low temperatures such, forexample, as -60 F. .and which does not increase NHsCOaR wherein R is analkyl group. Where R above is the ethyl group, Cal-Is, the resultingethyl carbamate, NHzCOzEb, is commonly termed urethane. However, where Rabove is analkyl group other than the ethyl group, e. g., methyl,propyl, butyl, etc., it is customary to identify the alkyl carbamate byreference to the particular alkyl group employed. Thus, the alkylcarbamate, NHzCOaCHa, is termed methyl carbamate; the

Application January 20,1945, Serial No. 573,812

alkyl carbamate, NHzCOzCsHl, is termed. propyl V carbamate; the alkylcarbamate, NH2CO2C4H9, is termed butyl carbamate, and so on. To theaccomplishment of the foregoing ends 5 and objects andin accordance withthis invention, there is incorporated in a hydrocarbon oil constitutingthe fuel whose cetane rating is to be raised a small quantity of anaddition agent, having the formula:

wherein R and R' are alkyl radicals which may be the same or diiferentand of which N-nitro N-b'utyl urethan; N-nitro N-isopropyl urethan;

N-nitro N-ethyl urethan; N-nitro N-methyl urethan and N-nitro N-butyl,butyl carbamate,

are typical.

The incorporation is preferably eflected by mixing the addition agentdirectly with the fuel which may then be fed to the combustion zone ofthe engine in the usual manner. Alternatively, the agent may beintroduced with the intake air in small amounts separate from the mainfuel spray or may be injected a few degrees ahead of the main spray.

The quantity of the agent to be added is advantageously in the order ofone percent (1%) by weight of the fuel treated, although a greater orless quantity may be employed to effect a greater or less change in thecetane number of the fuel as may be desired.

As may be seen by reference to the following table of comparative dataof a typical Diesel engine fuel in 9. treated and untreated state, thepresence of a small quantity of the addition agent results in thetreated fuel having a materially higher cetane number than the neatfuel. This increase in the cetane number is accompllshed withoutreduction in the flash point of the fuel, or at most with a relativelyminor lowering of the flash point. A corollary advantage, moreover,resides in the fact that the pour point 3 of the fuel is lowered thusimproving the utility of the fuel for general industrial and military 1Ne t l'uel N f in ea M 1% Add. 2% 'Add.

Flash Point (P. M.)- 203 F 113 F 23 F. Pom Point -.-l2 F -16 F -21. F.visms it (Baybolt). at v 85.2 secs. 35.6 secs".-- 85.4 secs. Water andSediment--. nil niL- nil. flniini'. 0.22 0 0.21 Carbon Residue 0.01 V 0.0. Cr 'bon Residueonlm 0.217, 0. a 1. nil. nil nil. Ocrrosion at 212F--... Passea.-.-. Faust.-- Passes. Distillation P 582 F 683 F 684 F.

(N. P. A 4 5 4 5 4.5. Octane Number 89 50 ,66. Diesel index 42.4. .7-40.8.

Poin 132.8" F.-.-. 182.8 F 131.9 F Gravity 81.9. .4 80.9. TemperatureDistilla- 1 113 .P 420 F 435" F 428 F 5% oil 448 F 467 F 454 F 455 F465' F 404 F.

470 F 477 F 478 F.

40 493 F 406 F 406 F.

60 517 F 517 F 621 F.

7 532 F 532' F 632 F.

so m F 550 F 564 F, I 90. 582 F 583 F 684 F.

95. 608 F 618 F 610 F.

E Pi: 640 F inc-18%---. sic-98.6%.

In the foregoing table the addition agent employed is N-nitro N.-butylurethan and it will be messes observed that the addition of 1% wt. ofthis compound (col. I11 raised the'cetane number of the neat fuel(col. 1) from 39 to the. generally recognised permissible minimum of 50.A further addition of 1% (col. III) raised the cetane num-' ber stillfurther to above the permissible mini:

. mum, without degradation of the flash point and with a furtherbeneficial lowering of the pour point. a v

Other members of the class having the general formula above mentionedexhibit the same general beneficial properties with variations in minoriegree and are equally suitable for the purpose.

Number The invention in its broader aspects is not limitedto thespecific steps, compositions, combinar tions and improvements describedbut departures may be'made' therefrom within the scope of theaccompanyingclaims without departing from the principles of theinvention and without sacrificing its. chief advantages.

WhatIclaimis: f

1. A fuel for compression ignition engines comprising a hydrocarbonDiesel oil containing a small quantity, at least sufiicient to increasethe cetane rating of said 011, of a material having the formula whereinR and R are alkyl radicals. 2. A fuel for compression ignition enginesc'omprising a hydrocarbon Diesel oil containing about.

1% by weight of a material having the formula 1 wherein R and R. areallwlradicals.

The following references are of record in the file of this patent:

' UNITED STATES PATENTS Name Date 2,274,629 Ellis Feb. 24, 19422,274,665 Clark Mar. 3, 1942 FOREIGN PATENTS Number Country Date 405,658Great Britain Feb. 5', 1934

